R/makeProjString.R

In rspatial/raster: Geographic Data Analysis and Modeling

# Author: Robert J. Hijmans
# Date :  January 2009
# Version 0.9
# Licence GPL v3



.newCRS <- function(projs) {

	if (is.null(projs)) {
		prj <- sp::CRS()
	} else if (is.na(projs)) {
		prj <- sp::CRS()
	} else if (nchar(projs) < 3) { 
		prj <- sp::CRS()
	} else {
		projs <- trim(projs)
		prj <- try(sp::CRS(projs), silent = TRUE)
		if (inherits(prj, "try-error")) { 
			warning(paste(projs, 'is not a valid PROJ.4 crs string')) 
			prj <- sp::CRS()
		}
	}
	return(prj)
}



# .makeProj <- function(projection='longlat', ..., ellipsoid="", datum="", asText=TRUE) {
	# prj <- rgdal::projInfo("proj")
	# ell <- rgdal::projInfo("ellps")
	# dat <- rgdal::projInfo("datum")
	# projection <- trim(projection)
	# ellipsoid <- trim(ellipsoid)
	# datum <- trim(datum)
	# if (!(projection %in% prj[,1])) {
		# stop("unknown projection. See rgdal::projInfo()") 
	# } else {
		# pstr <- paste('+proj=',projection, sep="")
		# projname <- as.vector(prj[which(prj[,1]==projection), 2])
	# }
	# pargs <- list(...)
	# if ( length(pargs) > 0 ) {
		# for (i in 1:length(pargs)) {
			# pstr <- paste(pstr, ' +', pargs[[i]], sep="")
		# }
	# }
	# if (ellipsoid != "") {
		# if (!(ellipsoid %in% ell[,1])) { 
			# stop("unknown ellipsoid. See rgdal::projInfo('ellps')") 
		# } else {
			# pstr <- paste(pstr, " +ellps=", ellipsoid, sep="")
# #			ellipname <- ell[which(ell[,1]==ellipsoid), 2]
		# }
	# }
	# if (datum != "") {
		# if (!(datum %in% dat[,1])) { 
			# stop("unknown datum. See rgdal::projInfo('datum')") 
		# } else {
			# pstr <- paste(pstr, " +datum=", datum, sep="")
# #			datumname <- as.vector(dat[which(dat[,1]==datum), 2])
		# }
	# }
	# # cat("Projection: ", projname[1], "\n")
	# crs <- .newCRS(pstr)
	# if (asText) { 
		# return(trim(crs@projargs))
	# } else {
		# return(crs)
	# }
# }